Electrical distributing system.



PATENTED MAY 5, 1903.

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No. 726,837 PATENTED MAY 5, 1903. L. ANDREWS. ELECTRIGAL DISTRIBUTINGSYSTEM.

APPLICATION FILED MAY 10 1902.

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PATENTED MAY 5, 1903.

L. ANDREWS. ELECTRICAL DISTRIBUTING SYSTEM APPLIUATION FILED MAY 10,1902.

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ELECTRICAL DISTRIBUTING SYSTEM.

APPLICATION FILED MAY'lO, 1902.

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- No. 726,837. PATENTED MAY 5, 1903.

. I L. ANDREWS. ELECTRICAL-DISTRIBUTING SYSTEM. 7

APPLIOATION FILED MAY 10, 1902.

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LEONARD ANDREWS, OF-IIASTINGS, ENGLAND.

ELECTRICAL DISTRIBUTING SYSTEM.

SPECIFICATION forming part of Letters Patent 0. 726,837, dated May 5,1903.

Application filed May 10, 1902. Serial No. 106,769. (No model.)

T0 aZZ whom it may concern.-

Be it known that I, LEONARD ANDREWS, a subject of the King of GreatBritain and Ireland, residing at Hastings, inthe county of Sussex,England, have invented Improvements in and Relating to ElectricalDistributing Systems, of which the following is a specification.

This invention has reference to improvements in electrical distributionsystems of the kind wherein duplicate mains or feeders (hereinaftercalled feeders) are used in connection with a distributing network ofconductors and with a common return-condoctor or return-conductors; andit has for object to provide simple, efficient, and reliable meanswhereby in the event of failure of either feeder from any cause, such asshortcircuiting thereof, any serious drop in pressure in the healthyorintact feeder at the end thereof remote from the electrical generatorand anyinterruption in the supply of current shall be prevented andwhereby the feeder that has failed can be automatically disconnectedfrom the portion of the distributing system to which the feeders areconnected and from the healthy feeder, so that the latter feeder willthen alone supply the said portion of the distributing system withcurrent.

Theinvention consists in various novel features of construction andcombinations and arrangements of parts, all as hereinafter described,and specifically pointed out in the claims.

In the accompanying illustrative drawings, Figure l is a diagram showingpart of an electrical single-phase distributing system em-p bodying thepresentinvention. Fig.2 is asimilar view to Fig. l, but showing meansfor automatically operating certain cut-out devices. Fig.3 is aplan of astatic relayshown in Fig. 2. Fig. 4 is a similar view to Fig. 2, butshowing modified means for automatically operating the cut-out devices.Fig. 5 is a diagram showing a further modified arrangement. Figs.

6 and 7 are diagrams showing the invention applied in connection with athree-phase dis tributing system.

According to the arrangement shown in Fig.1 the two feeders o I) of eachpair are at the end remote from the alternating-cu rrent generator 0each connected in series with one of two coils d and e, that are woundupon an iron coref and are connected together at g and to the externalportion 71, of the distributing network of the system, the two coils dand 6, with their coref, forming what is hereinafter called adiscriminating choking device. The arrangement is such that assuming thenumber of turns in the respective coils d and e on the discriminatingchoking device to be equal then under normal conditions the current willdivide itself equally between the two feeders a and b and flow inopposite directions around the two coils d and 6, so as to neutralizeeach others action on the core f, so that the only appreciable drop inpressure will be that due to the ohmic resistance of the circuit and thedifference in pressure between each feeder a or Z) and thereturn-conductor or return-conductors 2' will be equal for allvariations of the load in the portion lb of the distributing-circuitsupplied through the said feeders. If, however, the load be transferredfrom a point beyond the remote end of the feeders a b to any point ofeither of them between the discriminating choking device 01 e fandsource 0 of electric supplysay, for example, to the point kcaused, forexample, by a short circuit on the feeder a, the direction of thecurrent through the two coils d and e of the discriminating chokingdevice will then be such as to tend to magnetize the core f of thediscriminating choking device in the same direction, and as aconsequence there will be a considerable drop of pressure across it,depending upon the amount of the new load. If this load be caused by thesaid feeder a and return-conductor 2', Fig. 1, being short-circuited oneon the other, the drop across the discriminating choking device will bepractically equivalent to the electromotive force of the source ofsupply and the pressure across the said feeder and return-conductor willfall to zero, while that between the other feeder b and thereturn-conductor or corresponding return-conductor will remain normal,due to the action of the discriminating choking device, which then actsas a choking-coil. 'In this way the discriminating choking deviceprevents an excessive current passing to the damaged or inoperativefeeder. Each feeder a and b may be connected to the electric generator 0by a fuse n, as usual; also each feeder a and b may be provided at apoint near to the discriminating choking device (I e f and on the sidethereof next the electric generator 0 with a cut-out device (hereinaftercalled a switch) comprising, for example, a bent switch-lever having twoarms 0 0, whereof 0 is the operating-arm and 0 the contact-arm, whichnormally connects one of the feeders a or Z) to the corresponding coil01 or c.

The two coils d and c of the discriminating choking device may, as shownin Figs. 1 and 2, be formed by the two halves of a single coil the twoends of which are respectively connected to the two feeders C6 and Z),so as to be in series therewith, and the central portion of which isconnected to the portion or portions 7L of the distributing networksupplied through the said feeders, so that normally the current suppliedfrom the feeders flows in opposite directions through thetwo halves ofthe coil to the center thereof, or the two coils d and 6 may, as shownin Fig. 4, be arranged side byside and be connected together through abus-bar m, to which the portions 72, of the distributing system suppliedthrough the said feeders are connected. The coref, upon which the coilis wound, may be straight, as shown in Figs. 1 and 2, or of otherconvenient shape. It is, however, preferably closed on itself and may inthis case be in the form of a rectangular frame, as shown in Fig. 4.

To cause each feeder a and b when damaged to be automaticallydisconnected from the other feeder and the portion or portions 71 of thedistributing network which they normally supply with current, so thatsuch distributing network shall be supplied with current through thehealthy feeder alone, the switch-lever 0 0 of each feeder is adapted tobe normally held in the closed position and is controlled by electricalmeans which on the failure of the corresponding feeder automaticallyacts to cause the switch to open the circuit of the said feeder. Thearrangement shown for this purpose in Fig. 2 comprises a transformer thesecondary winding 5 of which has its circuit completed through a fusibledevice-as, for example, a length of wire qthat normally holds theswitch-arm 0 which is loaded in a position in which the switch-arm 0'closes the connection between the feeder and the corresponding coil d ore, the primary windingp of the said transformer being arranged in serieswith two conductors [and u, one of which-via, tis connected to theopposite feeder a or Z) to that to which the said switch 0 0 belongs andthe other of whichviz., u is connected to a contact point, pin, or plateo or 12', that is normally insulated, so that the circuit of the primarywinding 1) is normally open, but is adapted to be closed by acircuit-controlling device to (hereinafter called a relay in the eventof failure of the feeder controlled by the said switch. It will thus beunderstood that the switch 0 o, controllingeach feeder a 01' o, iscontrolled bya transformer adapted to be energized by current from theother feederb or a. The working of this arrangement is as follows: Whenthe two feeders a and b are intact and their actions on thediscriminating choking device 61 of balance each other, the transformersp s will be on open circuit and the switches 0 will be held closed; butin the event of failure of either feederfor example, 0;- the balancebetween the two feeders will be disturbed as hereinbefore described andthe relay to will be operated in a direction to complete the circuit ofthe primary winding 19 of the transformer p s, controlling the switch 00 of the damaged feeder, so that such primary winding will be, energizedby current from the healthy feedersay b-and will set up a current in thesecondary winding 8 of the said transformer of sufficient strength tomelt-the fusible device q, that held the loaded switch 0 o of thedamaged feeder in the closed position, and allow this switch-lever tomove under the action of gravity or a spring into a position todisconnect the damaged feeder from thediscriminatingchokingdevice. Therelay may, as shown in Figs. 2 and 3, conveniently be an electrostaticone and comprise a set of fixed plates 1, connected to the feeder a, anda set of fixed plates 2, connected to the feeder Z), so that each set ofplates 1 and 2 will be statically charged from the feeder to which it isconnected, and a spindle 3, that is provided with lever-arms 4t,carrying two sets of movable plates 5 and 6, arranged in proximity tothe statically-charged plates 1 and 2, the arrangement resembling aquadrant electrometer. Connected to one of the arms 4 is a contact-arm7, that is connected to earth through the said arm and spindle and isarranged between the two insulated points '22 "0, connected to theprimary windings p of the two transformers, for which purpose they maybe connected to the two sets of plates 1 and 2, respectively, as shown.The arrangement is such that normally theaction of the two sets ofstatically-charged plates 1 and 2, connected to the feeders a and b,respectively, on the two sets of plates 5 and 6, carried by thelever-arms 4, will balance each other and hold the contact-arm 7 in theopen or inoperative position; but in the event of the balance betweenthe two feeders being disturbed by the failure of one of the feeders, ashereinbefore described, the action of the statically-charged set ofplates 1 or 2, connected to the healthy feeder, will be unbalanced, andsuch plates will actuate the movable sets of plates 5 and 6 andlever-arms land cause the contact-arm 7 carried thereby to come incontact with one or other of the fixed contactpoints '0 or c andcomplete the circuit of the primary winding p of the transformercontrolling the switch 0 0 belonging to the damaged feeder and causethis switch to disconnect such feeder from the other feeder and thedistributing network h. I Each primary IIO winding is so constructed asto permit only of a small currentsay half an ampere--to pass through therelay when the circuit is completed. As the electrical pressure orpotential across the points of contact 7 and v or Q) will be very high,the action of the relay will be unaffected by oxidation of thecontactsurfaces.

In the modified arrangement shown in Fig. 4 the loaded arm 0 of eachswitch 0 o is held up by the armature 8 of one of two electromagnets 8and 8* that are controlled by a relay comprising two oppositely-arrangedelectroniagnets 9 9 and 10 10, each having its winding 9 or 10 in serieswith the secondary winding 3 of a small transformer the primary windingp of which is of higher resistance and arranged as a shunt betweenfeeder b or C6 and the return-conductor t' or one of thereturn-conductors 2' when there are two, as shown. The arrangement issuch that the two electromagnets 9 9 and 10 10 are separately energizedfrom the two feeders b and a, respectively, and exactly balance eachother under normal conditions of working, but will be unbalanced shouldeither feeder become accidentally short-circuited or its fuse n becomeblown. Mounted to oscillate between the two electromagnets is anarmature 11, the pivoted end of which is connected to end oneof thewinding of each of the two electromagnets 8 8 and the free end of whichcarries a contact l2,arranged to move between two fixed but adjustablecontacts 13 and 14, one of whichviz. ,13is connected to one end of thesecondary winding 3 of the transformer s 13, arranged to be energizedfrom the feeder b, and the other-viz, l t-is connected to one end of thesecondary winding 3 of the opposite transformer, arranged to beenergized from the feeder a. The other ends of the two secondarywindings s s are respectively connected to the second end of thewindings of the two electromagnets 8 8 in such a way, as shown, that thesecond end of the winding of each clectromagnet 8 or 8 willbe connectedto the secondary winding .9 of the transformer sp that is energized fromthe feeder controlled by the opposite electromagnet. The arrangement issuch that when the armature 11 is in its mid and inoperative positionthe circuit of each electromagnet 8.

8* will be open; but upon the balance of the relay-electromagnets 9 9and 10 10 being destroyed the relay-armature 11 will move to one side ofits mid-position andclose the circuit of the electromagnet 8 or 8",controlling the switch-lever 0 0 of the damaged feeder through thesecondary winding 3 of the transformer energized by the healthy feeder,the said electromagnet and switch then acting to open the circuit of thedamaged feeder. To

enable the healthy feeder to supply current to the distributing system hthrough the two coils (Z c of the discriminating choking device in thesame way that the two healthy feeders did so, the movable contactarm 0of l feeders a b each switch-lever 0 o is connected to one end of thecorresponding coil 61 or e, Figs. 1 and 2, and is arranged to workbetween two fixed contacts 15 and 16, one of which'-viz., l5is connectedto the feeder a and the otherviz., 16-to the second feeder b. Thearrangement is such that normally each switch contact-arm 0 connects thecoil d or e of the discriminating choking device to the correspondingfeeder a orb; but when the loaded switcharm 0 is released, ashereinbefore described, it moves the contact-arm 0 into a position inwhich it becomes disconnected from its own feeder and comes intoconnection with the fixed contact connected to the other feeder, whichthen becomes connected to the feeding ends of the two coils d 6. By thismeans'the resistance of the feeding portion of thecircuit is maintainednearly constant, whether one or both of the feeders a and b, which areof low resistance, is or are in use.

In some cases each switch may be arranged to short-circuit thediscriminating choking device when the circuit of either feeder isopened, and thus enable the healthy feeder to supply the distributingsystem h direct. In this case each feeder at and b has connected to itnear to the discriminating choking device d efand on the supply sidethereof, as shown in Fig. 4, one end of a conductor 17 or 17respectively, the other end of which is normally disconnect-ed from thecommon conductor or bus-bar m to which the two feeders a and b arenormally connected by the switches 0 def the cut-out devices, but whichis adapted to be automatically connected to such common conductor orbus-bar by the contact-arm o of the cut-out device 8 or 8 controllingthe opposite feeder, when such cut-out device is brought into operation,as hereinbefore described.

In some cases the switches o 0 may be arranged to be operated by handinstead of automatically. Fig. 1 shows such an arrangement. A voltmeter18 may be connected across each feeder a and b and the returnconductor2' or corresponding return-conductor, and the behavior of thesevoltmeters will indicate to an attendant in charge at the distributingend which feeder has become shortcircuited, and he will in consequencebe able to switch out the faulty feeder and leave the supply maintainedthrough the remaining healthy feeder. Such voltmeters may advantageouslybe employed when the switches are adapted to be operated automatically.

The feeders a and b may be supplied with alternating current eitherdirect from an alternating-current generator, as in Figs. 1, 2, and 4,or indirectly therefrom through transformers. Fig. 5 shows anarrangement of the latter kind, wherein a bus-bar 19 is supplied withalternate current from an alternate-current generator 0 through aeonductor a, and the distributing network his supplied through one ormore pairs of additional from one or more pairs of transformers 20, (twopairs are shown,) the primary windings 20 of which are energized fromthe bus-bar 19 and have fuses n in circuit therewith, and the secondarywindings 20 of which are connected to the additional feeders, each paira b of which is connected to the distributing network It through adiscriminating choking device cl 6 f and switches 0 0, arranged andoperating like those for the pair of main feeders.

The invention can also be applied in connection with electricaldistributing systems using polyphase electric currents. Thus for athree-phase distributing system a threephase one-to-one transformer ordiscriminating choking device having coils d c, 01 e and d 6 connectedto the duplicate pairs of sets of feeders (1'0? a and b 19 19 may beused, as shown in Fig. 6, with an electrostatic relay having fixedplates 1, 1", and 1, connected to the feeders ct a a respectively, andfixed plates 2 2 2, connected to the feeders b b 19 respectively, andthree movable plates 5, 5 and 5, normally arranged as shown and holdingthe movable contact '7 between the fixed contacts 'u. The set of feedersa, a and a is normally connected to the coils d, (1 and d by athree-pole switch 0 0 0 controlled by a small transformer 22 in themanner hereinbefore described by current from one of the feeders b b b-for example, bas shown. The set of feeders b b b is normally connectedto the coils e e e by another and similar three-pole switch 0' 0 0controlled by a second small transformer 23, energized by current fromone of the feeders say ain the other set of feeders a 01, a or insteadof the arrangement shown in Fig. 6 three distinct one-to-onetransformers or dis criminating choking devices like those shcwn inFigs. 1, 2, 4, and 5, with separate switches controlled by three relayslike those shown in Figs. 2 and 3, may be used, as shown in Fig. 7.

What I claim is- 1. An electric supply system comprising analternating-current generator, a conductor to be supplied with currentfrom said generator, a discriminating choking device, andduplicatefeeders including respectively separate coils of saiddiscriminating choking device.

2. An alternating-current distributing system comprising an electricgenerator, a conductor to be supplied with current from said generator,feeders connected to said electric generator, and coils connectedtogether and to said feeders and conductor neutralizing each othersaction when current flows simultaneously in the same direction throughsaid feeders, but acting as a choking-coil when current flows inopposite directions through said feeders.

3. An alternating-current distributing system comprising an electricgenerator, a conductor to be supplied therefrom, feeders connected tosaid electric generator, and discriminating choking device comprisingcoils connected together and to said feeders and conductor and amagnetic core for said coils, said core magnetized by said coils inopposite directions when said feeders are intact and traversed bycurrent passing from said electric generator to said conductor but tojointly magnetize said core in the same direction when one of saidfeeders fails.

4. An alternating current-distrib utin g system, comprising an electricgenerator, apair of feeders connected thereto, a pair of coils connectedtogether and each in series with one of said feeders, a core magnetizedby said coils, and a conductor connected to said feeders through saidcoils.

5. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, duplicatefeeders connecting said generator and conductor, coils each arranged inseries with one of said feeders, and a core normally magnetized inopposite directions by said coils when said feeders are intact butmagnetized in the same direction when either feeder fails.

6. An electrical distributing system comprising an alternating-currentgenerator, duplicate feeders connected at one end to said generator, acoil connecting the other ends of said feeder, an iron core extendingthrough said coil, and a distributing-conductor connected to the centralportion of said coil.

7. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and retarding thepassage of current from one feeder to the other, and cut-out deviceswhich separately control each feeder.

8. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, 'a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, anautomatic cut -out device connected to each feeder at the generator endthereof, and a cutout device controlling each feeder at the end thereofremote from said generator.

9. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, areturn-conductor between the first-mentioned conductor and saidgenerator, cut-out devices for opening and closing the circuit of saidfeeders at points near to said discriminating choking device, and avoltmeter connected across each feeder and return-conductor.

10. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, and meansfor automatically disconnecting either feeder, on failure thereof, fromthe other feeder and conductor.

11. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, a switchfor opening the circuit of each feeder on failure thereof, and meansadapted on failure of either feeder, to automatically open the switchcontrolling the circuit of such feeder.

12. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, a switchfor opening the circuit of each feeder on failure thereof, andelectrical means adapted on failure of either feeder, to automaticallyopen the switch controlling the circuit of such feeder.

13. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switchesadapted to open and close the circuits of said feeders at the endsthereof remote from said electric generator, and electric controllingdevices each adapted to be energized from one feeder and to cause theopening of the switch of the other feeder in the event of failure of thelatter feeder.

14. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current'from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminatin g choking device, electrical devicesarranged to control said switches and each adapted, when energized, tocause the corresponding switch to open and automatically disconnect itsfeeder from said discriminating choking device, and a relay that isinoperative on said electrical controlling devices when said feeders areintact but will, in the event of failure of either feeder, automaticallycome into action to energize the controlling device of the correspondingswitch and cause such switch to move into its open position.

15. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminating choking device, electrical devicesarranged to control said switches and each comprising an electricaltransformer the secondary winding of which includes fusible materialadapted to normally hold the corresponding switch in the closed positionagainst a force tending to automatically move itint-o the open position,and the primary winding of which is adapted to be placed in connectionwith a source of current, and a relay that is normallyinoperative butisadapted, in the event of failure of either feeder, to automaticallycomplete the circuit of the primary winding of the transformercontrolling the circuit of such feeder.

16. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminating choking device, electrical devicesarranged to control said switches and each comprising an electricaltransformer the secondary winding of which includes fusible materialadapted to normally hold the corresponding switch in the closed positionagainst a force tending to automatically move it into the open position,and the primary winding of which is connected at one end to the feedercontrolled by the opposite switch and at the other end to an insulatedcontact, and a relay that is normally inoperative but is adapted, in theevent of failure of either feeder, to automatically complete the circuitof the primary winding of the transformer controlling the circuit of thedamaged feeder through the healthy feeder. V

17. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking devicethrough'which said feeders are connected to said conductor and which isadapted to retard the passage of current from one feeder to the other,switches each adapted to open and close the circuit of one of saidfeeders at a point near to said discriminating choking device,electrical devices arranged to control said switches and each adapted,when energized, to cause the corresponding switch to open andautomatically disconnect said feeder from said discriminating chokingdevice, and an electrostatic relay that is arranged to be staticallycharged from said feeders and is normally inoperative but is adapted, inthe event of failure of either feeder, to come into action and cause thecontrolling device of the corresponding switch to become energized andcause such switch to move into the open position.

18. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminating choking device, electrical devicesarranged to control said switches and each comprising an electricaltransformer the secondary winding of which includes fusible materialadapted to normally hold the corresponding switch in the closed positionagainst a force tending to automatically move it into the open position,and the primary winding of which is adapted to be placed in connectionwith a source of current, an electrostatic relay that is staticallycharged from said feeders and is normally inoperative but is adapted inthe event of failure of either feeder, to automatically complete thecircuit of the primary winding of the transformer controlling thecircuit of such feeder.

19. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminating choking device, and electrical devicesarranged to control said switches, each switch when moved into positionto open the circuit of its feeder being adapted to connect the oppositefeeder to said conductor.

20. An electrical distributing system comprising an alternating-currentgenerator, a conductor to be supplied with current there from, feedersconnected to said generator, a discriminating choking device throughwhich said feeders are connected to said conductor and which is adaptedto retard the passage of current from one feeder to the other, switcheseach adapted to open and close the circuit of one of said feeders at apoint near to said discriminating choking device, and electrical devicesarranged to control said switches, each switch when moved into theposition to open the circuit of its feeder being adapted to connect theopposite feeder to said conductor through said discriminating chokingdevice.

21. An electrical distributing system com prising an alternating-currentgenerator, a conductor to be supplied with current therefrom, feedersconnected to said generator, a discriminating choking device comprisingcoils connected together and to said feeders and conductor and amagnetic core for said coils, and switches arranged near to saiddiscriminating choking device and controlling the circuits of saidfeeders, each switch being adapted when moved to disconnect its feederfrom one end of the corresponding coil, to connect the other feeder tothe said end of the coil.

22. An electrical distributing system comprising an alternating-currentgenerator, duplicate feeders connected thereto, adistributing-conductor, coils connected together and to said conductorand provided with an iron core, and switches each adapted when movedinto one position, to connect one of said coils to one of said feeders,and when moved into another position to disconnect said coil from theone feeder and connect it to the other feeder.

23. An electrical distributing system comprising an alternating-currentgenerator, duplicate feeders connected thereto through fuses, a coilprovided with an iron core, a distributing-conductor connected to thecentral portion of said coil, and two switches each adapted to connectone end of said coil to either of said feeders at the end thereof remotefrom said generator.

24. An electrical distributing system comprising an alternating-currentgenerator, duplicate feeders connected thereto, a conductor to besupplied from said generator, coils connected together and at a pointbetween them to said conductor, switches each comprising a loadedswitch-lever having a contact-arm connected to one end of each coil andadapted to be normally in connection with one of said feeders and whenreleased to antomatically move under the action of its load into aposition to disconnect such coil from said feeder and connect it to theopposite feeder, and electrical controlling devices for said switches,each controlling device being adapted to normally hold the correspondingswitch in the one position against the action of the load tending tomove it into a second position, and to release said switch and allow itto move into the second position, in the event of failure of thecorresponding feeder.

25. An electrical distributing system comrisin an alternate-current"enerator a consaid pair of coils, a pair of switches, a pair oftransformers having their primary windings connected to the conductor,and a pair of feeders connected to the secondary Windings of saidtransformers and each connected to said conductor through one of saidswitches and coils.

26. An electrical distributing system, comprising a polyphasealternating-current generator, main distributing-conductorscorresponding in number to the phases of the current supplied, pairs ofcoils with iron cores, the two coils of each pair being connectedtogether and, at a point between them, to one of said conductors, pairsof feeders connected LEONARD ANDREWS.

Witnesses:

WM. 0. BROWN, F. 0. SMITH.

